ATPase of basal bodies of Tetrahymena pyriformis.

The Ca2+-ATPase activity in basal bodies of Tetrahymena pyriformis was determined by cytochemical and biochemical methods. It was found that the sites of the Ca2+-ATPase activity are associated with the basal body microtubules. A method for the isolation of the basal bodies in a purified form in amounts for biochemical assay has been developed. Some properties of basal body ATPase were examined. It was established that the enzyme activity is specific for the hydrolysis of ATP and deoxy-ATP. The characteristic behaviour of the ATPase activity in response to divalent cations was assessed: the enzyme is stimulated by Ca2+ and inhibited by Mg2+. Basal body ATPase has a pH optimum of 7.5. Electrophoretic analysis of the protein composition of basal bodies revealed proteins with molecular weights of 56 and 43 kDa, corresponding to those of tubulin and actin respectively. It is suggested that the basal body ATPase may be involved in beating of the cilia, participating in the mechanochemical processes needed for motility of Tetrahymena pyriformis.

[Extraction and investigation of ATPase of Tetrahymena pyriformis cilia]. / Izvlechenie i issledovanie soliubiliziruemoi tritonom ATPazy resnichek tetrahymena pyriformis.

The ATPase-active proteins were solubilized from T. pyriformis of cilia by treatment of the cilia with the non-ionic detergent Triton X-100. The activity of Triton-solubilized ATPase is stimulated by Ca2+ and is sensitive to EGTA. Electron microscopy has demonstrated that treatment of the cilia with Triton results in demembranation of the cilia. An electrophoretic analysis of protein composition of the cilia before and after the removal of membranes and Triton extraction has shown that dynein and tubulin, the high molecular weight proteins of ciliary axonemes, are not extracted into solution; the Triton extracts were found to contain proteins with molecular weights of 104 000, 94 000, 71 000, 62 000 and 21 000, respectively. The ATPase was purified 10-25-fold by chromatography on DEAE-Sephadex A-50. Na-DS polyacrylamide gel electrophoresis revealed that the highly purified Ca2+-ATPase of cilia consists of two subunits with molecular weights of 93 000 and 85 000. The role of Ca2-ATPase in the mechanism of motility of T. pyriformis of cilia is discussed.

[Mimosa pudica adenosine triphosphatase]. / Issledovanie adenozintrifosfataz Mimosa pudica.

The morphological structure (pulvinus P1, P2 and P3) directly involved in the seismonastic movements of the Mimosa pudica leaf have been used to isolate: 1) "soluble" ATPase, loosely bound to pulvinus structures; 2) Ca, Mg-dependent ATPase, which is tightly bound to pulvinus structures and is extracted by a saline solution of high ionic strength, used to isolate actomyosin from muscles and non-muscle motile cells; 3) ATPase bound to the pulvinus membrane structures, which is solubilized by the detergents, e. g. Triton X-100 and Tween-80, and is similar to membrane ATPase. Physico-chemical and kinetic studies of the APSases have shown that Ca,Mg-ATPase is similar to the ATPases from muscle and non-muscle motile cells in a number of characteristics, e. g. solubility in saline solution of high ionic strength, aggregability in a solution of lower ionic strength, activation by bivalent metal ions, pH-optimum, specificity for substrates, etc. The protein composition of the ATPases has been determined by gel-electrophoresis in polyacrylamide gel. The molecular weight of purified Ca,Mg-ATPase from Mimosa pudica pulvinus is found to be 139 000. The role of ATPases in seismonastic movements of the Mimosa pudica leaf is discussed.